1. Field of the Invention
The disclosed embodiments of the present invention relate to a calibration method for a communication system and associated non-transitory machine readable medium, and more particularly, to an antenna diversity and beamforming coexistence method, wherein the method is applicable for a wireless communication device which supports both a transmitter/receiver (TX/RX) antenna diversity mechanism and a beamformer/beamformee mechanism, and an associated non-transitory machine readable medium.
2. Description of the Prior Art
In the field of wireless communication, antenna diversity effectively resists multi-path fading. The concept of antenna diversity is to select antenna(s) with stronger signal intensity or better signal quality from a plurality of antennas for data transmission and reception, to improve poor reception of a single antenna due to channel environment. Antenna diversity can be applied to a wireless local area network (WLAN). Beamforming is also adopted by some wireless communication systems, such as the IEEE 802.11n standard. Beamforming is a signal processing mechanism performed by a sensor array which directionally transmits/receives signals. Through adjusting parameters of basic elements of a phase array (PA), constructive interference is imposed on a signal coming from a certain angle while destructive interference is imposed on a signal coming from another angle. A beamforming mechanism is not generally supported by all of the IEEE 802.11n compatible products, however, as a result of its complexity and the lack of a uniform version. Further, a product with a beamforming mechanism may fail to comply with another when the two products are manufactured by different vendors which follow different versions of the beamforming standard. Subsequent IEEE 802.11ac standards therefore simplify and unify the beamforming mechanism in order to guarantee the compatibility.
Additionally, in conventional wireless communication systems, designers deal with the two mechanisms separately without an integrated solution. Coexistence of the two mechanisms will encounter mutual interference. For instance, if the antennal setting is switched (from one antenna to another) in response to antenna diversity mechanism during a beaforming process, the channel estimation previously made by the beamforming mechanism may be inappropriate for the new channel in response to the antenna switching. The reception of the link partner will become worse as a result of this mismatch. Therefore, there is an urgent need in this field for an antenna diversity and beamforming coexistence method which can dynamically decide an optimized configuration and thereby enable the two mechanisms to complement each other.